Solid-state storage devices (such as flash memory devices) have a downside in that the storage device is degraded each time that data is written to it. Specifically, each storage cell within the solid-state memory system can typically only be written to approximately 10,000 times and then it may no longer work.
Accordingly, wear-leveling methodologies are often employed to move data around to wear out the entire memory system simultaneously. These systems usually utilize extra “hidden” storage capacity (i.e. over-provisioning space) so that data may be swapped into these “hidden” areas to increase the likelihood of more uniform wear and to also allow the solid-state storage device to maintain its rated capacity even after the individual storage cells begin to fail. Typically the extra “hidden” storage capacity (i.e. over-provisioning space) is a fairly significant amount (e.g., 40% to the total capacity). Accordingly, a 500 gigabyte drive would have approximately 200 gigabytes of extra “hidden” storage capacity available for swapping.
Often, solid-state storage technology is used in data vaulting applications. As is known in the art, data vaulting is the process of storing a “snapshot” of the content of volatile memory at the time of a power/system failure. Accordingly, once the power/system is restored, the volatile memory may be repopulated with the data included within the snapshot and the system associated with the volatile memory may resume functioning as it had just prior to the power/system failure. Accordingly, through the data vaulting process, the impact associated with a power/system failure may be reduced, as the impacted system may quickly return to functionality once the power/system failure is rectified.
As data vaulting only occurs during a power/system failure event, the individual storage cells included within the solid-state storage device used for data vaulting are essentially only written to and read from once for each power/system failure event. Accordingly and due to such a low quantity of write operations, such data vaulting memory systems often do not require wear-leveling. For example and during a typical power/system failure event: power is lost; the content of dynamic DRAM is stored quickly within the solid-state data vault; and the content of the solid-state data vault is read upon restoration of the system and used to populate the dynamic DRAM. Accordingly, a solid-state data vault is only used in the event of a power/system failure.